title: Reassessment of estrogen receptor expression in human breast cancer cell lines.
abstract: BACKGROUND
  Human breast cancer cell (BCC) lines are used extensively in biomedical research and are classified as estrogen receptor (ER)-positive or ER-negative. We used flow cytometry (FCM), reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting (WB) to assess ER expression in human BCC lines reported as being ER-positive (MCF7, T-47D, ZR-75-1) or ER-negative (MDA-MB-231, SK-BR-3, MDA-MB-453, HCC1954) to determine the validity of this classification.
  
  
  METHODS
  ER was assessed in permeablized, fixed cells by FCM using two monoclonal anti-ERα antibodies and a polyclonal anti-ERβ antibody, in parallel with RT-PCR and WB.
  
  
  RESULTS
  All of the cell lines expressed ERα and ERβ. Indirect immunofluorescence indicated that it was membrane and cytoplasmic ER that was being detected by FCM. Down-regulation by fulvestrant confirmed it was ER.
  
  
  CONCLUSIONS
  These results demonstrate the importance of reassessing the ER status of human BCC lines that are used widely in biomedical research.
authors.affiliation: Department of Surgery, Faculty of Medicine, Kuwait University, Safat Zip Code 13110, Kuwait. fordchj@aol.com
authors.forename: Christopher H J
authors.initials: CH
authors.lastname: Ford
authors.forename: Maie
authors.initials: M
authors.lastname: Al-Bader
authors.forename: Bushra
authors.initials: B
authors.lastname: Al-Ayadhi
authors.forename: Issam
authors.initials: I
authors.lastname: Francis
mesh_terms: D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D015536:Down-Regulation; D047628:Estrogen Receptor alpha / Q000096:biosynthesis* / Q000235:genetics; D005260:Female; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D047628:Estrogen Receptor alpha; D012333:RNA, Messenger